TY  - BOOK
AU  - MacMahon, Brian,
AU  - Pugh, Thomas F.,
TI  - Epidemiology: principles and Methods 
SN  - 0-316-54259-8
U1  - 614.4'9 
PY  - 1970///,
CY  - Boston
PB  - Little, Brown
KW  - Epidemiologia -
ER  -